Division of Bacteriology and Parasitology, Tulane National Primate Research Center, Covington, LA, USA.
J Neuroinflammation. 2013 Jul 18;10:88. doi: 10.1186/1742-2094-10-88.
Lyme neuroborreliosis (LNB), caused by the spirochete Borrelia burgdorferi, affects both the peripheral and the central nervous systems. Radiculitis or nerve root inflammation, which can cause pain, sensory loss, and weakness, is the most common manifestation of peripheral LNB in humans. We previously reported that rhesus monkeys infected with B. burgdorferi develop radiculitis as well as inflammation in the dorsal root ganglia (DRG), with elevated levels of neuronal and satellite glial cell apoptosis in the DRG. We hypothesized that B. burgdorferi induces inflammatory mediators in glial and neuronal cells and that this inflammatory milieu precipitates glial and neuronal apoptosis.
To model peripheral neuropathy in LNB we incubated normal rhesus DRG tissue explants with live B. burgdorferi ex vivo and identified immune mediators, producer cells, and verified the presence of B. burgdorferi in tissue sections by immunofluorescence staining and confocal microscopy. We also set up primary cultures of DRG cells from normal adult rhesus macaques and incubated the cultures with live B. burgdorferi. Culture supernatants were subjected to multiplex ELISA to detect immune mediators, while the cells were evaluated for apoptosis by the in situ TUNEL assay. A role for inflammation in mediating apoptosis was assessed by evaluating the above phenomena in the presence and absence of various concentrations of the anti-inflammatory drug dexamethasone. As Schwann cells ensheath the dorsal roots of the DRG, we evaluated the potential of live B. burgdorferi to induce inflammatory mediators in human Schwann cell (HSC) cultures.
Rhesus DRG tissue explants exposed to live B. burgdorferi showed localization of CCL2 and IL-6 in sensory neurons, satellite glial cells and Schwann cells while IL-8 was seen in satellite glial cells and Schwann cells. Live B. burgdorferi induced elevated levels of IL-6, IL-8 and CCL2 in HSC and DRG cultures and apoptosis of sensory neurons. Dexamethasone reduced the levels of immune mediators and neuronal apoptosis in a dose dependent manner.
In this model, B. burgdorferi induced an inflammatory response and neuronal apoptosis of DRG. These pathophysiological processes could contribute to peripheral neuropathy in LNB.
莱姆神经Borreliosis（LNB），由螺旋体 Borrelia burgdorferi 引起，影响外周和中枢神经系统。神经根炎或神经根炎症，可引起疼痛、感觉丧失和无力，是人类外周 LNB 最常见的表现。我们之前报道，感染 B. burgdorferi 的恒河猴会发展为神经根炎以及背根神经节（DRG）炎症，DRG 中的神经元和卫星神经胶质细胞凋亡水平升高。我们假设 B. burgdorferi 诱导神经胶质细胞和神经元细胞中的炎症介质，而这种炎症环境会引发神经胶质细胞和神经元细胞凋亡。
为了在 LNB 中建立周围神经病变模型，我们将正常恒河猴 DRG 组织外植体与活 B. burgdorferi 体外孵育，并通过免疫荧光染色和共聚焦显微镜鉴定免疫介质、产生细胞，并验证组织切片中 B. burgdorferi 的存在。我们还从正常成年恒河猴的 DRG 细胞中建立了原代培养，并将培养物与活 B. burgdorferi 一起孵育。培养物上清液通过多重 ELISA 检测免疫介质，同时通过原位 TUNEL 测定评估细胞凋亡。通过评估存在和不存在不同浓度的抗炎药物地塞米松时上述现象，评估炎症在介导凋亡中的作用。由于施万细胞包绕 DRG 的背根，我们评估了活 B. burgdorferi 诱导人施万细胞（HSC）培养物中炎症介质的潜力。
暴露于活 B. burgdorferi 的恒河猴 DRG 组织外植体显示 CCL2 和 IL-6 在感觉神经元、卫星神经胶质细胞和 Schwann 细胞中的定位，而 IL-8 则在卫星神经胶质细胞和 Schwann 细胞中可见。活 B. burgdorferi 诱导 HSC 和 DRG 培养物中 IL-6、IL-8 和 CCL2 水平升高，并诱导感觉神经元凋亡。地塞米松以剂量依赖的方式降低免疫介质和神经元凋亡的水平。
在该模型中，B. burgdorferi 诱导了 DRG 的炎症反应和神经元凋亡。这些病理生理过程可能导致 LNB 中的周围神经病变。
